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Limit calling pmc_hook to when the interrupt comes while running userspace.

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We may enable interrupts from within the callback, e.g. in a data abort
during copyin. If we receive an interrupt at that time pmc_hook will be
called again and, as it is handling userspace stack tracing, will hit a
KASSERT as it checks if the trapframe is from userland.

With this I can run hwpmc with intrng on a ThunderX and have it trace all
CPUs.

Obtained from:	ABT Systems Ltd
Sponsored by:	The FreeBSD Foundation
This commit is contained in:
Andrew Turner 2016-05-24 12:06:56 +00:00
parent b5994a5c26
commit 974692e3bf
1 changed files with 2 additions and 1 deletions
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3
sys/kern/subr_intr.c
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@ -317,7 +317,8 @@ intr_irq_handler(struct trapframe *tf)
td->td_intr_frame = oldframe;
critical_exit();
#ifdef HWPMC_HOOKS
if (pmc_hook && (PCPU_GET(curthread)->td_pflags & TDP_CALLCHAIN))
if (pmc_hook && TRAPF_USERMODE(tf) &&
(PCPU_GET(curthread)->td_pflags & TDP_CALLCHAIN))
pmc_hook(PCPU_GET(curthread), PMC_FN_USER_CALLCHAIN, tf);
#endif
}